Brush holder for electrical apparatus



April A. STOPPANY BRUSH HOLDER FOR ELECTRICAL APPARATUS magma Filed April 5, 1935 2 Sheets-Sheet 1 Aprfifi 2% 119%. A: STQPPANY BRUSH HOLDER FOR ELECTRICAL APPARATUS Filed April 5, 1935 2 SheetsSheec 2 Patented Apr. 28, 1936 UNITED it STATES PATENT OFFICE BRUSH HOLDER FOR ELECTRICAL- APPARATUS on-the-Rhine, Germany, a joint-stock pany of Germany com- Application April 5, 1935, Serial No. 14,934 In Italy December 10,1934

11 Claims.

My invention relates to improvements in brush holders for electrical apparatus, and more particularly in brush holders comprising a holding member in which the brush is guided for being shiftable towards and away from the device making electric contact therewith such as a commutator, means for shifting said brush towards said device, and means for pressing the brush on its guide. One of the objects of the improvements is to provide a brush holder of this class which is composed of a small number of parts, and in which the wear of the operative parts is reduced. Another object of the improvements is to provide a holder in which vibration of the brush on its holder causing rapid wear of the commutator is prevented. Another object of the improvements is to provide a brush holder which may be manufactured at low cost.

With these and other objects in view my invention consists in providing a single member such as a two-armed lever which acts on the brush in axial direction for shifting the same towards the said electrical device and also in transverse direction for pressing the same on its guide.

For the purpose of explaining'the invention an example embodying the same has been shown in the accompanying drawings in which the same reference characters have been used in all the views to indicate corresponding parts. In said drawings,

Fig. 1 is a sectional elevation showing the brush holder andthe brush mounted therein,

Fig. 2 is an elevation viewed from the left in Fig. 1,

Fig. 3 is an elevation partly in section showing the. brush, the spring acting thereon and the hood enclosing the said spring removed from the holding .member,

Fig. 4=is a top plan view of Fig. 1,

Fig. 5 is a sectional elevation showing the spring and the hood removed'from the holder andthe brush,

Fig. 61s a top plan view of Fig. 3, and

Fig. 'I is a somewhat diagrammatical elevation partly in section showing a modification.

In the example shown in Figs. 1 to 6 I have shown. a. brush holder which is intended for 'cooperation with a commutator ll 01 a dynamo or electric motor. The said brush holder comprises abody ladapted to be fixedto the usual ringllocatedl around the commutator and having several brush holders mounted thereon. The

saidiholding member I is made integral with a somewhat-cylindrical portion la formed with a pair offeyes. lb having a tubular and longitudinally slotted pivot bolt 4 fixed therein. To the bottom part of the holding member I an -shaped leaf spring I5 is secured which provides an elastic guide for a brush I0. To the top part of the said brush a pin 6 is fixed by means of a sleeve 5 secured to the said pin and formed with arms 50!. embracing the brush ID. The said arms 5a. are formed with outwardly bulged portions 5!) adapted when the brush is worn to bear on the leaf spring l5 and thus to limit the outward movement of the brush and to hold the metallic arms 5a out of engagement with the commutator H, as is shown in Fig. 1 in dotted lines.

On the pin 6 a hood 8 is guided the closed top part of which is formed with an opening 812 which is slidable on the pin 6, and within the said hood a coiled spring I is located which bears with one end on the top part of the hood and with its opposite end on the brush ID, the said spring tending to urge the brush out of the hood and inwardly toward the axis of the electrical machine into engagement with the commutator II. The spring 1 is constructed so as to exert as near as possible uniform axial pressure on the brush, and for this purpose its diameter is as large as possible, and in the unloaded state its length is about nine times that of the length of the spring mounted in the holder and acting on a brush of normal length, while when the brush is completely worn its length is about five times that to which it is compressed when a brush of normal length is mounted in the holder.

The brush I0 is acted upon by a single member 2 which tends to shift the same in the direction of its axis toward the commutator, and which also acts thereon in a transverse direction for holding the same in close engagement with the spring I5. As shown in the figures the said member comprises a two-armed lever 2 which is articulated on the pivot bolt 4, and which has one arm 2a acting on the closed top of the hood and through the same and the spring I on' the brush l0 and the other arm 2b acting on the brush ID in a transverse direction near the bottom part thereof. When the brush I0 is worn and it is desired to put in a new brush, the pin 6 is moved upwardly and the lever 2 is rocked outwardly and into the position shown in Fig. 1 in dashes and dots, whereupon the brush and its pin 6 may-be removed, and a new brush may be inserted. Fig. 3 shows the hood and a new brush ready for being inserted in the holder. It appears therefore that the lever 2 is only occasionally rocked outwardly and while no pressure acts thereon so that the pivot bolt 4 and the lever 2 bearing thereon are practically not subject to wear.

As is shown in Fig. 1, the arm 2a is greater in length than the arm 2b and the ratio of the said arms is such that the arm 2b acts on the brush in a transverse direction with the desired pressure.

The top wall of the hood is formed with two depressions Ba which are engaged by the bifurcated end of the arm 2a. Thus the arm 2a provides an upper guiding member for the hood and the brush I0. Thus the guide for the brush which consists of the spring I5 and the arms 2a has a great length, the said length being about the double of that of the fresh brush. The length of the said guide remains constant also as the wear of the brush proceeds. Therefore the brush is safely guided in radial direction with respect to the commutator. By pressing the same with its bottom part on the elastic member [5 vibration of the brush is prevented.

The pin 6 is made from insulating material. Its gravity and that of the spring I is small and the mass of the whole system is small, and therefore rhythmic vibration of the brush is made impossible. This is important, because thereby the wear of the commutator, and particularly the formation of waves thereon is prevented, so that the commutator has an increased life.

When the brush is worn the bulged portions 5b seat themselves on the spring I 5, so that the metallic portions 5a are held out of engagement with the commutator thus preventing rapid wear thereof.

When the brush is completely worn, and the member 5a is in the position shown in Fig. l in dotted lines, a circular groove 6a of the pin 6 is flush with the top wall of the hood 8, which indicates that a new brush must be inserted.

At opposite sides the hood 8 is formed with cut out portions 8d for the passage of the brush. Further, the hood is provided with four inwardly directed noses on which the spring I is held in position when the brush has been removed as is shown in Fig. 5. Further, by means of the said noses the hood is guided with its bottom part on the brush.

When the commutator is to be turned or ground it is only necessary to lift the parts shown in Fig. 3 away from the commutator a distance of about inch and to place the brush on the arm 2b of the lever 2. By enclosing the parts of the brush holder within the cylindrical portion la and the hood 8 the said parts are protected against an arc discharge and break down. The cylindrical portion la is formed with an upwardly and outwardly directed tapering extension 9. If therefore an arc is produced around the margin of the commutator which tends to increase in diameter, the said arc climbs upwardly on the said extension 9 and to the pointed top part thereof, where it is extinguished by a current of air delivered from the space between the stator I2 and the rotor I3 as indicated in Fig. 2 by an arrow 9:. I

The noise caused by the operation of the brush holder is reduced, because vibration of the brush is prevented.

The brush is guided in the holder in a reliable way by being engaged by the arm 2 in axial and transverse direction. Therefore the pin 6 may be dispensed with as is shown in Fig. 7. In this construction the radial dimension of the holder is reduced which may be desirable in some cases.

In the construction shown in Fig. 7 the brush cannot be removed by pulling the pin 6 outwardly, and therefore the upwardly directed arm 2' of the lever 2 carries a finger 2" which is articulated on the said arm at I4. If it is desired to remove the brush the finger 2" is turned to the side whereupon the hood 8 and the brush ll] may be readily removed. In the operation of the apparatus lateral displacement of the finger 2 is prevented in a suitable way, for example by means of a spring l6 engaging in a groove made in the hub of the finger 2".

Since the brush arrangement illustrated herein may be disposed at any point around the circumference of the commutator II, in describing the apparatus, the term outwardly will mean in a direction away from the commutator, and the term inwardly will be understood to mean in the direction toward the commutator.

I claim:

1. A brush holder for electrical apparatus, comprising a brush, a pin fixed to said brush axially thereof, a hood in which said pin and brush are guided for movement in the direction of their axis, a spring within said hood in position for acting on said brush and pin for shifting the same i in said direction, a holding member in which said brush is guided during said movement, and a member acting on said hood and spring in a direction for shifting said brush in said axial direction and also acting on said brush transversely thereof for pressing the same on its guide.

2. A brush holder for electrical apparatus, comprising a brush, a holding member in which said brush is guided for movement in the direction of its axis, said brush and holding member being provided with cooperating stops adapted to limit said axial movement of said brush, and a member acting on said brush in a direction for shifting the same in said axial direction and also in a direction transversely thereof for pressing the same on its guide.

3. A brush holder for electrical apparatus, comprising a stationary holding member, a brush guided in said holding member, a two-armed lever pivotally mounted intermediate its length on said holding member and having one arm acting on said brush in the direction of its axis and the other one acting on said brush transversely thereof near the current collecting end thereof, the connection between the first named arm and said brush being variable, whereby the brush is shiftable in its holder out of operative position to permit the second named arm of said lever to clear the brush and the lever, to be rocked with its first-named arm out of position for axial engagement.

4. A brush holder for electrical apparatus, comprising a holding member, a brush guided in said holding member, a two-armed lever pivotally mounted intermediate its length on said holding member, a finger pivotally mounted on one of the arms of said lever, said two-armed lever and finger being in position for acting with one arm of said lever against said brush in a direction transversely thereof for pressing the same on its guide and with said finger acting on the brush to urge it in the direction of its axis.

5; A brush arrangement for commutators of electrical apparatus or the like, comprising, in combination, a stationary supporting frame carried by said apparatus, a brush disposed adjacent said frame, a lever rotatably J'ournalled upon said frame intermediate its length, a spring seat member disposed outwardly of said brush, a compression spring disposed between said brush and said seat member, one end of said lever bearing upon said spring seat member in a direction axially of said brush to urge the latter inwardly against the commutator, and the other bearing against the inner end portion of said brush transversely thereof to press it resiliently against a portion of said frame.

6. A brush arrangement for commutators of electrical apparatus or the like, comprising, in combination, a stationary supporting frame carried by said apparatus, a resilient brush guiding member on said frame, a brush disposed adjacent said frame to slidably bear against said resilient guide member, an angular lever rotatably journalled upon said frame intermediate its length, a spring seat member disposed outwardly of said brush, a compression spring disposed between said brush and said seat member, one end of said lever bearing upon said spring seat member in a direction axially of said brush to urge the latter inwardly against the commutator, and the other bearing against the inner end portion of said brush transversely thereof to press it resiliently against said resilient guide portion of said frame.

7. A brush arrangement for commutators of electrical apparatus or the like, comprising, in combination, a stationary supporting frame carried by said apparatus, a brush disposed adjacent said frame, a hood inclosing the outer end of said brush and having means thereon for guiding said brush during relative movement, a spring seated within said hood and bearing against the outer end of said brush, a lever rotatably journalled intermediate its length upon said stationary frame, one end of said lever bearing inwardly upon said hood to press the brush resiliently upon the commutator, and the other end bearing laterally against the lower end portion of said brush to press it against a portion of said frame whereby it is properly guided during operation of said apparatus.

8. A brush arrangement for commutators of electrical apparatus or the like, comprising, in combination, a stationary supporting frame carried by said apparatus, a brush disposed adjacent said frame, a hood inclosing the outer end of said brush and having means thereon for guiding said brush during relative movement, a. coil spring seated within said hood in axial alignment with said brush and bearing against the outer end thereof, a lever rotatably journalled intermediate its length upon said stationary frame at a point laterally of the common axis of said brush and spring, one end of said lever bearing inwardly upon said hood to press the brush resiliently upon the commutator, and the other end bearing laterally against the lower end portion of said brush to press it against a portion of said frame whereby it is properly guided during operation of said apparatus.

9. A brush arrangement for the commutators of electrical apparatus or the like, comprising, in combination, a stationary supporting frame carried by said apparatus, a brush disposed adjacent said frame and in sliding contact with a portion thereof, a lever rotatably journalled upon said frame intermediate its length and provided with a pair of arms of unequal length, a spring seat member disposed outwardly of said brush, a compression spring disposed between said brush and said seat member, one arm of said lever bearing upon said spring seat member in a direction axially of said brush and the other bearing against the inner end portion of said brush transversely thereof, whereby the brush is resiliently urged inwardly toward the commutator and also against a portion of said stationary frame with different degrees of pressure.

10. A brush arrangement for the commutators of electrical apparatus or the like, comprising, in combination, a stationary supporting frame carried by said apparatus, a brush disposed adjacent said frame, a pair of spaced lugs on said frame provided with aligned bearing openings, a slotted tube bearing pin passing through said openings, a lever rotatably jo-urnalled intermediate its length upon said slotted tube bearing pin and arranged to bear resiliently upon said brush axially thereof to press it into contact with said commutators, and transversely thereof to press it slidably against a portion of said stationary frame to guide it during operation of the apparatus.

11. A brush arrangement for the commutators of electrical apparatus or the like, comprising, in combination, a brush, a stationary support frame carried by said apparatus and having a guiding surface against which said brush is slidably disposed, a two-armed lever pivotally mounted intermediate its length upon said stationary frame, the end of one arm disposed outwardly of said brush and adapted to move generally axially thereof during its pivotal movement, and the end of the other arm disposed laterally of the brush and adapted to move transversely thereof, a single compression spring-disposed between one of said arms and the brush, whereby both arms are made to resiliently urge the brush in the respective directions toward the commutators and toward said guiding surface.

AMBROGIO STOPPANY. 

